Abort. To terminate an operation prematurely when it is seen that the desired result will not occur.
Advection. In weather, the term used for the horizontal transport of heat by the wind.
Absolute altitude. The actual distance between an aircraft and the terrain over which it is flying.
Advisory Circular (AC). An FAA publication that informs the aviation public, in a systematic way, of nonregulatory material.
Accident. An occurrence associated with the operation of an aircraft which takes place between the time any person boards
the aircraft with the intention of flight and all such persons have disembarked, and in which any person suffers death or
serious injury, or in which the aircraft receives substantial damage. (NTSB 830.2)
Aeronautical Information Manual (AIM). A reference publication for pilots.
Airworthiness Directive (AD). A regulatory notice sent out by the FAA to the registered owner of an aircraft informing
him or her of a condition that prevents the aircraft from meeting its conditions for airworthiness. Compliance requirements
will be stated in the AD.
Adiabatic process. In weather, the change of the temperature of air without transferring heat. In the adiabatic process,
compression of the air mass results in the warming of the air; conversely, the expansion of the air mass results in cooling
of the air.
Administrator. The FAA Administrator or any person to whom he or she has delegated authority in the matter concerned.
Aeronaut. A person who operates or travels in a balloon or airship.
Aeronautical Decision-Making (ADM). A systematic approach to the mental process, used by pilots to consistently
determine the best course of action in response to a given set of circumstances.
Aeronautics. The branch of science that deals with flight and with the operations of all types of aircraft.
Aerostat. A device supported in the air by displacing more than its own weight of air.
Automated flight service station (AFSS). An air traffic facility that provides pilot briefings and numerous other services.
AGL. Above ground level.
Aircraft. A device that is used or intended to be used for flight in the air.
Airport. An area of land or water that is used for the landing and takeoff of an aircraft.
Altimeter. A pressure reading device that, when properly calibrated, indicates the height of the aircraft above mean sea
level (MSL). An altimeter is a required instrument in a balloon, as directed by 14 CFR part 31, Airworthiness Standards:
Manned Free Balloons.
Altimeter setting. The station pressure (barometric pressure at the location the reading is taken) which has been corrected
Glossary
for the height of the station above sea level.
Ambient air. Air surrounding the outside of a balloon envelope.
Anabatic winds. In weather, a wind that blows up the slope of a hill or mountain due to increased heating along the valley
walls.
Annual inspection. A maintenance term directed by 14 CFR part 91, section 91.409, which states that “no person may
operate an aircraft unless, within the preceding 12 calendar months, it has had—(1) an annual inspection…and has been
approved for return to service…”
Apex line. A line attached to the top of most balloons to assist in inflation or deflation. Also called crown line or top
handling line.
Approved. Approved by the FAA Administrator or person authorized by the Administrator.
Archimedes’ Principle. The Greek mathematician’s principle of buoyancy, which states that an object (a balloon) immersed
in a fluid (the air) loses as much of its own weight as the weight of the fluid it replaces.
ATC. Air Traffic Control.
Automatic Terminal Information Service (ATIS). The continuous broadcast (by radio or telephone) of recorded noncontrol,
essential but routine, information in selected terminal areas.
Automatic Weather Observing System (AWOS). Continuous broadcast (by radio or telephone) of weather conditions at
selected locations.
Ballast. Gas ballooning term; used to control buoyancy, and therefore altitude, during flight. Ballast, usually in the form of
sand or water, is carried aloft by the gas balloon at launch. As the balloon pilot needs to adjust altitude, a small amount of
ballast is jettisoned overboard, thereby reducing the gross weight of the balloon at that point in time. The balloon will then
rise to a new pressure altitude, where it will remain until there is another dynamic change in the lift equation.
Balloon. A lighter-than-air aircraft that is not engine driven, and that sustains flight through the use of either gas buoyancy
or an airborne heater.
Balloon Federation of America (BFA). A national association for balloon pilots and enthusiasts in the United States, and
affiliated with the National Aeronautic Association. Information about the BFA can be found at www.bfa.net
Balloon flight manual. A manual containing operating instructions, limitations, weight, and performance information,
which must be available in an aircraft during flight. Portions of the flight manual are FAA approved.
Basket. That portion of a hot air balloon that carries the pilot, passengers, cargo, fuel, and instruments.
Blast valve. The valve on a propane burner that controls the flow of propane burned to produce heat.
Bowline knot. Pronounced boh' lin. A common knot that is easy to tie and untie and will not slip.
Btu (British thermal unit). A measurement of heat. The amount of heat required to raise 1 pound of water from 60 to 61 °F.
Buoyancy. In ballooning, when the balloon is zero weight and is neither climbing nor falling.
Burn. A common term meaning to activate the main blast valve and produce a full flame for the purpose of heating the air
in the envelope.
Burner. See Heater.
Capacity. See V olume.
Captive balloon. Commonly used to describe a balloon that is permanently anchored to the ground.
Category. According to Title 14 of the Code of Federal Regulations: (1) As used with respect to the certification, ratings,
privileges, and limitations of airmen, means a broad classification of aircraft. Examples include: airplane; rotorcraft;
glider; and lighter-than-air; and (2) As used with respect to the certification of aircraft, means a grouping of aircraft based
upon intended use or operating limitations. Examples include: transport, normal, utility, acrobatic, limited, restricted, and
provisional (14 CFR part 1).
Ceiling. The lowest broken or overcast layer of clouds or vertical visibility into an obscuration.
CFR. Code of Federal Regulations.
Charles’ Law. If the pressure of a gas is held constant and its absolute temperature is increased, the volume of the gas will
also increase. This principle is particularly relevant in gas ballooning.
Checklist. A tool that is used as a human factors aid in aviation safety. It is a systematic and sequential list of all operations
that must be performed to properly accomplish a task.
Class. According to Title 14 of the Code of Federal Regulations: (1) As used with respect to the certification, ratings, privileges,
and limitations of airmen, means a classification of aircraft within a category having similar operating characteristics.
Examples include: single-engine; multiengine; land; water; gyroplane; helicopter; airship; and free balloon; and (2) As used
with respect to the certification of aircraft, means a broad grouping of aircraft having similar characteristics of propulsion,
flight or landing. Examples include: airplane, rotorcraft, glider, balloon, landplane, and seaplane.” (14 CFR part 1)
Coating. A thin synthetic added to the surface of balloon fabric to lessen porosity and ultraviolet-light damage.
Cold front. In weather, the leading edge of a cold air mass displacing a warmer air mass.
Cold inflation. Forcing cold air into the envelope, giving it some shape to allow heating with the heater.
Commercial pilot. A person who, for compensation or hire, is certificated to fly an aircraft carrying passengers or cargo.
Controlled airspace. Airspace designated as Class A, B, C, D, or E within which air traffic control service is provided to
some or all aircraft.
Convection. Generally, the transfer of heat energy in a fluid. As applied to weather, the type of heat transfer occurring in
the atmosphere when the ground is heated by the sun.
Cooling vent. A vent, in the side or top of the balloon envelope, which opens to release hot air, and that closes after the
release of air automatically.
Crew chief. A crewmember who is assigned the responsibility of organizing and directing other crewmembers.
Crown line. A line attached to the top of most balloons to assist in the inflation and deflation of the envelope. Sometimes
referred to as apex line or top handling line.
Currency. Common usage for recent flight experience. In order to carry passengers, a pilot must have performed three
takeoffs and three landings within the preceding 90 days. In order to carry passengers at night, a pilot must have performed
three takeoffs and three landings to a full stop at night (the period beginning 1 hour after sunset and ending 1 hour before
sunrise).
Dacron. The registered trade name for polyester fabric developed by DuPont.
Declination. A term useful in map reading. Declination is the difference between true north and magnetic north, and is
usually defined on an aviation sectional map or a topographical map.
Density altitude. As defined in the Pilot’s Handbook of Aeronautical Knowledge, FAA-H-8083-25, “pressure altitude
corrected for nonstandard temperature.” However, a more pertinent definition is that in the Airman’s Information Manual,
which explains density altitude as being nothing more than a way to comparatively measure aircraft performance. See
paragraph 7-5-6 of the AIM for a complete discussion.
Deflation panel. A panel at the top of the balloon envelope that is deployed at landing to release all hot air (or other lifting
gas) from the envelope. A parachute top is a form of deflation panel.
Designated pilot examiner (DPE). A person appointed by the Administrator who may accept application for certificates,
administer practical exams, and issue pilot certificates. DPEs are considered to be technically qualified, and must have a
good industry reputation for professionalism and integrity.
Drag line. A gas balloon term used to describe a large, heavy rope, deployed at landing, which orients the balloon (and rip
panel) to the wind, and transfers weight from the balloon to the ground, creating a landing flare.
Drop line. A rope or webbing, which may be deployed by the pilot to ground crew to assist in landing or ground handling
of a balloon.
Envelope. Fabric portion of a balloon that contains hot air or gas.
Equator. The widest diameter of the envelope.
Equilibrium. When lift equals gravity, as in level flight. Equilibrium at launch is typically that temperature at which after
the balloon has been inflated and is standing up (erect), the ground crew is able to hold the balloon in place by resting their
hands lightly on the basket.
Fabric test. Testing of the envelope fabric for tensile strength, tear strength, and/or porosity. Fabric tests are specified by
each balloon manufacturer.
False lift. See Uncontrolled Lift.
Federal Aviation Administration (FAA). The federal agency responsible to promote aviation safety through regulation
and education.
Federal Communications Commission (FCC). The federal agency which regulates radio communication and communication
equipment in the United States.
Flameout. The inadvertent extinguishing of a burner flame.
Flare. The last flight maneuver by an aircraft in a successful landing, wherein the balloon’s descent is reduced to a path
nearly parallel to the landing surface.
Flight review. Required for all certificated pilots every 24 months in order to retain pilot in command privileges. A flight
review consists of at least 1 hour of flight training and 1 hour of ground training.
Flight time. According to Title 14 of the Code of Federal Regulations, the time from the moment the aircraft first moves
under its own power for the purpose of flight until the moment it comes to rest at the next point of landing.
Flight visibility. According to Title 14 of the Code of Federal Regulations, the average forward horizontal distance, of an
aircraft in flight, at which prominent unlighted objects may be seen and identified by day and prominent lighted objects
may be seen and identified by night.
fpm. Feet per minute.
Flight Standards District Office (FSDO). Field offices of the FAA, which deal with certification and operation of aircraft.
Gauge. A device for measuring. Required gauges on a hot air balloon are the envelope temperature gauge (pyrometer) and
the fuel quantity gauge for each fuel tank. Most balloons also have fuel pressure gauges.
Gondola. Portion of a gas balloon that carries the pilot, passengers, cargo, ballast, and instruments.
Gore. A vertical section of fabric, often made of two vertical, or numerous horizontal panels, sewn together to make a
balloon envelope.
Global Positioning System (GPS). The Global Positioning System is a series (or “constellation”) of satellites circling the
Earth, each broadcasting a unique signal. These signals, usually three or more, are detected by electronic units, and, thru
triangulation and time delay sensings, provide an extremely accurate location readout of the GPS receiver. Many balloon
pilots carry a small GPS unit on board the balloon to determine location, ground track and ground speed.
Ground crew. Persons who assist in the assembly, inflation, chase, and recovery of a balloon.
Ground visibility. According to Title 14 of the Code of Federal Regulations, prevailing horizontal visibility near the earth’s
surface as reported by the United States National Weather Service or an accredited observer.
Handling line. A line, usually ¼-to ½-inch diameter rope, attached to a balloon envelope or basket, used by the pilot or
ground crew to assist in the ground handling, inflation, landing, and deflation of a balloon.
Heater. Propane-fueled device to heat air inside the envelope of a balloon, often referred to as a burner.
Helium. A light, inert gaseous chemical element mainly found as a natural gas in the southwestern United States. Used to
inflate gas balloons and pilot balloons.
Helicopter Emergency Medical Service (HEMS) Weather Display. A product of the Aviation Digital Data Service, this
computer program give weather information, both real-time and forecast, for a 5 kilometer square area nationwide. It can
be viewed and downloaded at www.weather.aero/HEMS
Hydrogen. The lightest of all gaseous elements. Commonly used in Europe for inflating gas balloons. Flammable by itself
and explosive when mixed with oxygen. As opposed to helium, hydrogen is easily manufactured.
Hypoxia. An aeromedical term; means “reduced oxygen” or “not enough oxygen.”
International Civil Aviation Organization (ICAO). An agency of the United Nations, which has codified principles and
techniques of international air navigation and fostered the planning and development of international air transport to ensure
safe and orderly growth. ICAO has produced many international treaties to standardize aviation; the United States is a
member of the ICAO, and as such, has agreed to many of the standardization efforts, most notably in the area of airspace
nomenclature.
Igniter. A welding striker, piezo sparker, matches, or other means used to ignite the balloon pilot flame.
Incident. An occurrence other than an accident, associated with the operation of an aircraft, which affects or could affect
the safety of operations.
Indicated altitude. The altitude shown on a properly calibrated altimeter.
Inoperative. Not functioning or not working.
Instructions for Continued Airworthiness. A manual published by an aircraft manufacturer specifying procedures for
inspection, maintenance, repair, and mandatory replacement times for life-limited parts.
Integrated Airman Certification and Rating Application (IACRA). An online application system that allows for the
issuance of student, private and commercial pilot certificates without generating paperwork; all certificate application and
approved is performed through the use of electronic “signatures.”
Instrument. According to Title 14 of the Code of Federal Regulations, A device using an internal mechanism to show
visually or aurally the attitude, altitude, or operation of an aircraft or aircraft part. There are only two instruments required
in a hot air balloon: vertical speed indicator (VSI) and altimeter.
Katabatic winds. A wind produced by the flow of cold, dense air down a slope in an area subject to radiational cooling.
Mountain winds are the most common form of katabatic winds.
Kevlar® A registered trademark for a DuPont Corporation product, a synthetic fiber created in 1965 which has a strength
factor 5 times that of steel. Frequently used in balloon systems for suspension cables and control lines of various types.
Generally, Kevlar® is used for the core of a suspension line, and will have a cover or sheath over the core, as Kevlar ® is
ultraviolet light sensitive.
Life-Limited. An aircraft part whose service is limited to a specified number of operating hours or cycles. For example,
some balloon manufacturers require that fuel hoses be replaced after a certain number of years.
Light Aircraft. Any aircraft with a maximum takeoff weight of less than 12,500 pounds. All presently FAA-certificated
balloons are light aircraft.
Limitations. Restrictions placed on a balloon by its manufacturer. Examples are maximum envelope temperature and
maximum gross weight.
Log. A record of activities: flight, instruction, inspection, and maintenance.
LTA. Lighter-Than-Air.